Friday, February 19, 2010

LSAT Definition Assumption: Logical Reasoning Task Standard

Today we'll tackle one of the most ubiquitous tasks, definition assumption. All test prep companies have their own take on how to spot assumptions, but as per usual, here at Zen of 180 we have a slightly more discriminating classification system. There are four types of assumption questions on the LSAT; for today we'll be focused on the more prevalent definition assumption, which asks you to specify the gap between a term used in the stimulus' evidence and also in its bridge or conclusion. The other assumption tasks include finding a missing direct logic link, definition shift, or a fails to consider [possibility].

The answer in definition assumption task will be a direct link between the evidence and the conclusion (or infrequently the bridge) of the stimulus. While that sounds easy enough, the task can be deceptively difficult if you don't know what you're looking for. Unlike with some tasks, it is hit-or-miss on pre-phrasing answers for definition assumption; this is because there are numerous ways of stating the link, and if you can't generalize your pre-phrased answer, you'll choose an attractive distractor.

To avoid this issue, we advise our clients to pre-phrase a statement that links the relevant elements of the evidence to the conclusion across the gap, something that sounds like, "The answer will directly link the Executive Director to the executive board." The difference between prephrasing the gap and prephrasing the answer is similar to saying, "I need to get across the river here" and "I need to drive across the one-lane wooden bridge." The former prephrase will allow you to consider any answer that accurately links across the--in this case literal--gap, while the latter will be too specific for many test takers to find the credited response translated into LSAT speak.

At first blush, such distinctions between executive boards and Executive Directors or between gaps and answers can appear to be inconsequential; however, the LSAT gets plenty of test takers to gloss over a crucial definition shift between evidence and conclusion. This test is not kind to careless readers, and the specificity of language employed is very different from everyday language.


The explanations below are for the two sample PrepTests from October 1996 and June 2007, which had a combined five questions devoted to this type of assumption task.


   

Below is the frequency that this task has been asked on modern LSATs, although we are currently in the process of analyzing the pre-2007 LSAT assumption questions. It averages 9.0% of the points on a modern LSAT, and you can reasonably expect that at least four points will be devoted to finding the definition gap between the evidence and conclusion.
 
41 times
on LSATs since 2007
9.0% of LR
(5 per LSAT, range 3-10)
?%growth from pre-2007

Definition assumption has a relatively high point-density on the LSAT. This task requires you to utilize the prerequisite skills described in argument proceeds by and main conclusion, and is frequently tapped for both distractors and answers in fix by adding. Thus, the footprint of assumptions is larger than even the 5 points on a modern LSAT indicates.